NYC-WTC_000152373

NYC 9/11 Public Portal Document

//Following the Water * / -Droughts have spawned some of history’s great human migra­ tions. But drought can have an effect on a micro level, too. Wit­ ness what researchers have dis­ covered about the activity of cyanobacteria in the desert. Cyanobacteria (sometimes called, misleadingly, blue-green algae) are photosynthesizing or­ ganisms, usually unicellular, that often grow in long, threadlike col­ onies. In the desert, cyanobac­ teria, with fungi and lichens, often make up the organic crust that develops on rocks and soil. Studying soils from badlands in Spain, researchers from Arizona ^rte University and Bordeaux ^MversitymFrance have discov- e^fthat some cyanobacteria mi- ^ate within the soil as the mois­ ture level changes. Cyanobacteria just beneath the surface appeared on the surface within minutes af­ ter the soil was wetted, and disap­ peared as the soil dried out. Adding compounds that inhibit­ ed energy use by the cyanobac­ teria stopped the process com­ pletely, indicating the organisms were not just hitching rides on the water, via surface tension, as it moved. The researchers, writing in Nature, say the ability of cyan­ obacteria to follow water may be crucial to their survival in harsh conditions.

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